A telecommunication arrangement with modems (MCO; MCPE) having a receiving module (URx; DRx) able to receive channels of signals via a communication line (LN). The arrangement preferably operates according to the xDSL protocol. The receiving module of each modem is associated to storage means (USN, DSN; LDN) storing a “channel condition model” corresponding to operational conditions of the channel, preferably to the “worst case”. The channel condition model is determined by previously measured operational conditions of this channel and/or by a channel condition model managed externally to the modem, and which is stored in the storage means before the initialization of the modem. In different variants, the channel condition model is a model of the noise level, the signal-to-noise ratio, the actual or the maximum bitloading (bi) per carrier of the channel and/or mathematical operations on these. The channel condition model is further updated at regular time intervals during initialization or showtime. The modem may be located at the Central Office (CO) or at the Customer Premises Equipment (CPE). The receiving module (URx) of the CO modem (MCO) may receive the channel condition model from the central office management device via a management interface. The channel condition model may also be transmitted from the central office management device to the receiving module (DRx) of the CPE modem (MCPE), and channel condition measurement information may even be fed back.